Typically, when a joint, an arm or a leg is fractured or injured, the injured joint, arm, or leg is fixed using a cast, a plaster cast, or a brace, and the like, to enable a smooth treatment.
Conventionally, to fix such an injured joint, arm, or leg, a bandage and plaster were used to apply a plaster cast, but such plaster is not only heavy, but cannot be reformed after being solidified. Moreover, since the plaster is degraded or damaged when exposed to moisture, it is difficult for the patient to bathe or shower, and there are also disadvantages such as the area on which the plaster cast is applied being poorly ventilated.
Due to such reasons, casts which are not damaged even when taking a bath or shower, or having a structure that allows air to easily pass through are being developed recently, and the thermoplastic mesh shaped body disclosed in U.S. Pat. Nos. 6,673,029 and 4,143,655 is an example thereof.
In particular, the mesh shaped body 100 disclosed in U.S. Pat. No. 6,673,029 is made in a mesh shape of which the size of the apertures 120 is relatively large, as illustrated in FIGS. 1a and 1b. Here, to ensure sufficient strength for firmly supporting and protecting a part of the body, the material forming the mesh shape is formed by laminating 6-12 layers of a fiberglass fiber 110 to form a sheet shape, and then cutting this sheet shaped material such that the shape of the apertures form a hexagonal mesh array. With such a cast (mesh shaped body), not only is it difficult to laminate multiple layers of the resin impregnated fiberglass fiber, but when the cast is pulled in order to perform a procedure for applying the cast on a body part of the patient, the sides defining the mesh shape are stretched (hereinafter referred to as “elongation”). Consequently, the thickness of the sides is reduced such that not only is the strength of the cast reduced, but due to excessive elongation of the sides in a lengthwise direction, there is a disadvantage in that the connecting parts are unable to maintain a flat plane, and thus some of the connecting parts protrude sharply in a vertical direction and contact the skin of the patient such that the patient feels discomfort.
Moreover, when multiple layers of the resin impregnated fiberglass fiber are laminated as described above, the surface of the fiber layer becomes unsmooth due to uneven impregnation during the process of impregnating with the resin, and since the patient may feel discomfort due to the cast when wearing the cast consisting of such an unsmooth surface, in order to form a smooth surface a separate layer must be reformed in the area contacting the skin of the patient, and thus the production process is complicated.
Furthermore, even when, as above, the separate layer is formed on the surface contacting the skin of the patient, since the surface of the layer disposed therein is not smooth, the parts laminated thereon may not be smooth, and thus, when the thickness of the layer contacting the skin of the patient is not greater than a predetermined thickness, the patient may continue to experience discomfort.
In addition, in the above patent, in order to produce the cast as a mesh shaped body, after first forming a fabric using the fiberglass fiber, the apertures are created by cutting rhombus shapes from the fabric, and thus strands of the fiberglass fiber may be loosened from the fabric. In this case, the strength of the cast may be weakened, and when the loosened parts of the strands are those impregnated with resin, these parts become pointed and thus irritating the skin of the user is a concern.
It is necessary for a cast or a plaster cast to have sufficient strength in order to maintain a fractured bone in the proper position or to suppress movement in the arms or legs such that treatment is accelerated, swelling in the injured parts of the arms or legs is stabilized, and body parts are protected from impact or injury.
For example, when a bone is fractured, it is advantageous for the strength of the cast in the direction of the body to be high to allow the fractured bone to be maintained in the proper position, and for this reason, the ‘geometrically apertured protective and/or splint device comprising a re-mouldable thermoplastic material’, in which air passes through open through-holes and which is structured to be high in strength in the longitudinal direction and relatively lower in strength in the circumferential direction, has been proposed in U.S. Pat. No. 7,985,192.
The splint device 200 proposed in the above patent document is composed of a splint member 210 and a spacer member 220, as illustrated in FIGS. 2a and 2b, and here, the splint member 210 is formed as a mesh shaped body such that a plurality of rhombus shaped openings 220 are formed between them, and due to such a structure, by restricting elongation in a lengthwise direction of a side while allowing stretching to be easy in a direction parallel to a first axis and a third axis, the shape of the rhombus formed in the mesh shaped body may be easily deformed (hereinafter, this is referred to as “deformation” so as to be distinguished from “elongation”, which indicates stretching of the length of the side), and thereby an attempt was made to reduce the difficulty of the medical procedure.
However, despite the splint device disclosed in the above patent document being easily deformed such that the medical procedure for applying the splint device on a patient is comparatively easy, since the entire cross section of the mesh shaped splint member 210 is formed from a polycaprolactone composite material in which ligno-cellulose is added, not only is the strength relatively weak, but there is a disadvantage in that the elongation in a lengthwise direction of the side may continue to occur such that the thickness of the side decreases and thus weakens the strength thereof.
Therefore, it is necessary to develop a cast in which elongation in a lengthwise direction of the side is restricted during a medical procedure for applying the cast on a body part of the patient to enable the strength of the cast to be maintained, the apertures in the mesh structure are allowed to be easily deformed according to the external shape of the body part of the patient to enable the medical procedure of applying the cast to be easily performed, and the patient does not feel discomfort when wearing the cast; and to develop a production method for the same.